Joseph e



(No Model.)

J. R. FRANCE.

BLASTING GAP.

No. 356,712. Patented Jan. 25, 1887.

UNITED STATES PATENT OFFICE.

JOSEPH B. FRANCE, OF NEW YORK, N. Y., ASSIGNOR TO THE METALLIC CAPMANUFACTURING COMPANY, OF SAMEJELACE.

BLASTlNG-CAP.

SPECIFICATION forming part of Letters PatenBNo. 356,712, dated January25, 1887.

Application filed November 2, 1886. Serlnl No. 21'l,834. (No model.) I ITo all whom it may concern: 1

Be it known that I, JOSEPH R. FRANCE, a citizen of the United States,residing at New York, inthe county of New York, and State of New York,have invented new and useful Improvements in Blasting-Caps, of which theaccording to my invention.

following is a specification. v

My invention relates to certain improvements in blasting-caps or'exploders for explodi'ng nitro-glycerine, dynamite, gelat-inepowder, orother explosive material. It is the object of my invention to rendersuch detonators instantaneous in action throughout the cartridge to beexploded, thereby increasing the force and obtaining'results which arebetter andgreater.

- It is also my purpose'to provide a construction by which there shallbe free egress to the burning gas or spark to the mixture to bedetonated and to increase the ignition surface, whereby the burninggasfrom the fuse, or. the spark, if electricity is used, reaches aconsiderable surface at one and the sameinstant.

My invention consists in the several novel features" of construction andcombinations of parts hereinafter fully set forth, and definitelypointed out in the claims following this specification.

Inthe accompanying drawings, Figure 1 is adetail view of a fulminate-capconstructed Fig. 2- is a sectional view of the same incased, in a coppershell.

-Heretofore and prior to my invention caps for blasting purposes haveusually been made by partly filling a copper shell with fulminate ofmercury, or a compound of such fulminate with chlorate of potash,gun-cotton, or other substances, said compound being forced into orcompressed by a plunger within the metallic shell, usually filling itabout one-quarter full. These caps or detonators are usually ignited orfired by a fuse, though an electric spark is sometimes used, andalthough they are apparently instantaneous in action they are, in fact,not so, since the first grains or atoms of fnlminate'receive the burninggas (or the spark,

.if electricity is used) and .in turn communicats the shock to the nextgrains, and so on until its inertia is extended throughout thecaitridgeto be exploded. The more nearly instantaneous orsimultaneous thisexplosion can be made the better and greater are the results obtainedfrom the powder, dynamite, or other compound exploded by the detonator.

In the drawings referred to the reference numeral 1 designates a cap ordetonator formedof' any suitable substance-such as fulminate of mercury,or fnlminate mingled with chlorate of potash or other compound,

such as a high grade of gun-cotton-tlie substances employed beingmingled in "suitable proportions. A quantity of the compound is thencompressed into the shells in the ordinary. A

plunger-presses, the plungers being provided with a point by which aconical chamber or recess, 2, is centrally formed in the mixtureextending to or nearly to the bottom of the shell or cap 1. p,

The manner of forming these caps is as follows: The material composingthe cap is placed in a copper shell, 3, of suit-able caliber, and isthen acted upon by a plunger operated by a suitable press. The plungeris of such form as to produceihe conical opening of a suitable depth,and at the same time compress the explosive of which the cap is formed,the latter usually occupying about one-fourth the depth-of the shell 3.

The opening or chamber 2 is of conical form, preferably, but may be madeof other forms, if desired. So, also, the opening may penetrate to ornearly to the lower end of the fulminate-cap, or be of any suitabledepth, without departing from my invention. a

' Having thus described my invention, what I claim is 1. A blasting-capor detonator consisting of a compressed body of fulminating material orcompound,having an open chamber extending from one end toward its otherend, in combination with a shell partly filled only by said

